Monthly Archives: January 2012

The first known image of a living Myanmar snub-nosed monkey, acquired by camera trap. Image on public domain, 2012.

We want to bring every month a post of this bulletin with natural history network itens that catch our attention. Every month we will write the article and along with it bring to light his view on things, such as news, related blog entries, reviews on books, artistry and so on.

The Blind Watchmaker, by Richard Dawkins. If you still haven’t quite understood how evolution could shape all lifeforms on our planet, you’ll be fascinated by how everything is so simple and perfectly possible after reading this great book by one of the most influent biologists of our time.

ArtHere are some pictures that came to light in this month and in my opinion deserve an place under the sun:

“Carcharodontosaurus sanagasta” by Jorge Antonio Gonzalez – Gonzalez made this 10 meter long model of polyester resin with Ernesto Rodriguez, Cecilia and James Dellagiovanna, Sebastian Perez Parry and Maria de los Angeles Meza, with Gonzalez himself participating in sculpture and art direction. A great detailed model with eyes that don’t show the expression of monsters we usually see in those theropods. This is the main point that made me like it.

“Coelodonta nihowanensis” by Chen Yu – skull and reconstruction of this obscure rhinoceros from Early Pleistocene of China. Chen’s gallery on DeviantArt is full of amazing compositions featuring extinct mammals that usually are out of the focus of the sight of the general reader.

“Fisher King revisited” by Scott Hartman – Hartman’s technical drawings are, along with Gregoy Paul’s, a reference for most of the recent popular paleontological pictures we see in internet. A place he deserve, of course, with his pictures being product of deep research. This time, Spinosaurus aegypticus skeleton, which the original finds were destroyed by a bombardment during the World War II.

“The Vicious Lizard of Madagascar” by Julio Lacerda – this composition make us think we are looking direct into a photograph of a long-gone creature. Lacerda’s pictures really catch my attention for being digital without looking ”plastic”, for being very accurate anatomically and making the dinosaurs looking the animals they were, not monsters. Yes, I really don’t like dinosaurs being depicted as creatures from hell with an insatiable thirsty for blood and destruction.

The maximum rate of mammal evolution, measurements about evolution of body size in Mammals suggest that for a mouse to reach the size of an elephant, it would take about 24 million generations or 10 million years.

Like this:

This post is just a note about something I have been witnessing more frequently in my daily life. I use to wait for the bus at a terminal attached to a subway station in the south of the city. As a lover of animals, I always have my attention caught by any species occurring in this chaotic surrounding that makes a city, mainly birds, which are the class that concentrates most of my interest.

A rock pigeon that I photographed at the garden of Museu Paulista of University of São Paulo. I used to go there more often to see the birds.

During the day I use to see, near the place I work, kiskadees (Pitangus sulphuratus), rufous-bellied thrushes (Turdus rufiventris), rufous horneros (Furnarius rufus), plain parakeets (Brotogeris tirica), swallows, hummingbirds and, of course, pigeons (Columba livia) and sparrows (Passer domesticus). And those last two are the focus of this post. A bus terminal is a naturally crowded and busy place, even more if attached to a subway station. And at the time I return home, this crowd increases drastically. And a place with a high flow of people demands places to sell food. And a high flow of people and food means a filthy mess, and that attracts animals that feed on that mess, something quite predictable. It’s amazing how human beings, used to this automatic daily life where everything has to be quick, sometimes pass, without noticing, over the birds that feed on all this filth. Yes, they transmit diseases, but they are living beings after all. And blaming the animals for being there is ironic, since Man himself disseminated them from the Old World during his transcontinental comings and goings.

Well, returning to the focus: the animals ended up getting used to such an environment and not being intimidated with the presence of humans, associating them to an easy source of food. However, the birds don’t seem to get intimidated by the vehicles either, and that’s their biggest danger in places like that. Today I watched an old lady who wildly threw cheese breads to the pigeons. And since I was sitting next to her, a flock of them (thirteen birds, I counted them) was surrounding me. And this happened on a platform with several people in a hurry that eventually kick the pigeons and move their food to the street. And in the dispute between pigeons and even sparrows that don’t seem to fear the larger pigeons (which they eventually attack), the vehicles arrive and end up crushing an unaware bird that preferred to remain disputing a piece of snack rather than flying away to ensure a longer stay among the living ones. In the same day I saw a pigeon being crushed and another one having its tail trapped by the wheels of a bus (but this once escaped). Today I saw some daring sparrows carrying pieces of food almost as big as themselves to the cover of the platform, and a small chick that was cuddled in the middle of the street, bathed by the evening sun, until a bus came, whose second pair of wheels the sparrow wasn’t able to escape from. Even if they are considered plagues and that there’s a need to control their population to avoid the lack of hygiene and proliferation of diseases, it’s sad to witness so frequently the death of those animals, which is the result of a poor planning and management of the environment created by men.

One of the big questions without an answer in our knowledge of the world is “How many species are there on the Earth?” and we are far from having even an approximation of the real number. There are, for sure, thousands of speculations, varying hugely between them, but we could say that a mean value would be about 10 million species, while we currently know only about 1.5 million. And that’s exactly the point I’m interested in focus here: the number of species we currently know. Are we sure that all we consider species are in fact so?

Probably everybody has already heard about a situation where a group of organisms once considered a single species where in fact two distinct ones, like the African elephants Loxodonta africana and L. cyclotis, where the latter was only classified as a distinct species by 2010.

As for people in general, if you ask them to say the name of an animal, they would probably tell the name of a mammal, or perhaps a bird, reptile or if you are lucky, they will say “butterfly” or “spider” and that’s all. Well, that’s nothing wrong with it, but I think people should realize that those animals, like lions or elephants, are just a small particle in the entire world of species.

I currently hold an undergraduate research at Unisinos (Universidade do Vale do Rio dos Sinos / University of the Sinos Valley), Brazil, working at the IPP (Instituto de Pesquisa de Planárias / Planarian Research Institute) with land planarians’ ecology, physiology and behavior.

For those who don’t know (and I know there are a lot of people who don’t), land planarians are terrestrial flatworms, belonging to the phylum Platyhelminthes, in the group Tricladida. They are usually found under rocks or logs in forested areas, but also in gardens or elsewhere. Many of them are very sensible to light, high temperatures or extremes of drought and moisture, so that their presence may indicate a more conserved area.

Two specimens of Luteostriata abundans (Graff, 1899), a land planarian from southern Brazil. Photo by Piter Kehoma Boll.

Land planarians are a group still poorly known and, despite a high number of species having been described in the last decades, many more are yet to be, and those already described are not well understood in what concerns their ecology and behavior.

The first described land planarians were defined based only on external features, mainly their body shape, color and eyes arrangement. But Ludwig von Graff, in his 1896 work “Über die Morphologie des Geschlechtsapparates der Landplanarien” (On the Morphology of the Reproductive Apparatus of Land Planarians) already noticed the importance of internal morphology, mainly that of the copulatory apparatus, for a more precise identification at the species level.

Despite that, the following years were still marked by publications concerning only external features, like the work of Schirch (1929). Only by the 1950’s a real focus was started to be given in the structure of male and female organs. Most of the following works on land planarians’ descriptions, like those of the Marcus and Froehlich couples, focused on the copulatory apparatus together with external features, so giving a more trustful description of new species. By this moment, the reproductive structures became essential for the classification of new species and eventually led to the creation of new genera.

Drawing of several land planarian species. Extracted from Schirch, 1929.

Drawings of internal and external structure of several land planarians. Extracted from Marcus, 1951.

In 1990, Ogren and Kawakatsu published an index of all known species of land planarians in family Geoplanidae by that time. They noticed that many species still classified in the genus Geoplana, like those described by Schirch, were never reviewed and were still only known by external features, so that their position within Geoplana may not be correct. To avoid this misclassification, they created a new “temporary genus”, which they called Pseudogeoplana (false Geoplana) and put all those dubious species in it to stay there until someone reviewed them and could place them in the correct genus, either the original Geoplana or other one.

But guess what? Ogren and Kawakatsu did that in 1990 and now we are in 2012 and the situation remains the same. Those poor planarians species are still waiting in that taxonomic shelter until someone moves them to the place they belong to.

So how can we be sure about anything from those species? They were described in 1929, almost a century ago, and no one cared about them since then. And I guess the same occurs in other less cute and attractive groups, so while we describe hundreds or thousands of new species every year, other hundreds or thousands are left behind, forgotten inside dusty glasses in the zoological museums worldwide.

As my friends know very well, I’m a fervent opponent of Jack Horner’s ideas. So naturally I had to start a series for analyzing and counter attacking some of his wackiest theories about dinosaur which, I hope, aren’t brainwashing an entire generation of paleoartists. Let’s get to know the star of the first post of the series: the Triceratops.

People might remember some time ago, it was everywhere in the news: “Triceratops didn’t exist”. That’s BS, even Horner himself said so. What he actually meant is that the ceratopsian dinosaur Torosaurus is nothing but an aged Triceratops: over the years the frill of – presumably male only – Triceratops would grow to the astounding size of Torosaurus‘ frill, about 2.5 meters (8.5 feet) long.

So in reality what should have been in the news is “Torosaurus didn’t exist”. In zoological nomenclature, a basic principle is that when a species received two different names, the earliest correctly published name, called senior synonym, takes precedence and thus should be used to name the species, excluding the later name (junior synonym). And since Triceratops was named before Torosaurus, Triceratops is the senior synonym and has to be the official one. But naturally media figured most mainstream people don’t know what a Torosaurus is, so their solution was to mess everything up and make some sensationalism, because that’s very surprising.

Naming issues aside, there are a few points about this theory that just seem off to me:

A little less known aspect of Horner’s theory (or maybe not so much anymore since he already released a paper about it) is that before becoming Torosaurus, Triceratops became something else first, and that is Nedoceratops (formerly Diceratops).

Nedoceratops skull. Photos by Andrew A. Farke, from Wikipedia, 2011

Nedoceratops have a long history of debates about its validity as a separated species or as a synonym for Triceratops (the small windows in the frills simply being caused by pathologies, for example). For Horner, the holes in the frill indicate the beginning of the transformation into Torosaurus, but that’s about where things get weird.

Drawing of the two Torosaurus skulls by Marsh, 1893.

Really now, how exactly does a hole form outta nowhere? So okay, Horner demonstrates that Triceratops’ frill is not entirely solid, some areas are thinner, and these are about the same areas where the holes appear in Torosaurus, so it apparently makes sense Torosaurus to be an old Triceratops, but even if dinosaur’s bones were very plastic and enabled many transformations as they grew, the bone retroceding and becoming so thin to the point where it disappears and leaves a hole is something not even sheer open-mindness is able to accept.

Reason number one is ceratopsian growth in general. Let’s use Protoceratops as the example since there are plenty of skeletons from individuals of varying ages, from baby to adult:

Protoceratops growth series. Photo by Harry Nguyen, 2008.

As you can see, the holes in the frill are present even in the youngest individuals. And if people can use Psittacosaurus quilled tail as an excuse to put quills in all other ceratopsians tails, then darn it, I WILL use baby Protoceratops as an argument that baby ceratopsians maintain holes in their frills all the way to adulthood, which takes us to reason number two, which is the baby Triceratops skull itself:

So there, he does have some kind of holes in his barely formed frill. But these quickly disappear, as shown by the rest of the growth series. Maybe the thinner areas of Triceratops’ frill is a heritage of his baby form, maybe that part is naturally thinner for whatever reason. The point is that if it was true that Torosaurus is an old Triceratops, then the holes should have been present in all the younger forms just like Protoceratops, no matter how small they are compared to other ceratopsians.

But I give credit where credit is due. Horner presented solid evidence: the bones of Triceratops are spongy, which is characteristic of young individuals, which means that, true, Triceratops may not represent fully grown individuals. Still, it’s a long shot to assume Torosaurus is the mature form.

There is one little detail Horner overlooked in his theory: there IS a dinosaur that is bigger and is similar to Triceratops – even more than Torosaurus –, and whose remains were found in the Horseshoe Canyon formation in Alberta, which not only isn’t that far from Montana, but is also known to contain remains of dinosaurs also present in the Hell Creek formation, including Triceratops.

This dinosaur is called Eotriceratops xerinsularis, described in 2007 by Xiao-Chun Wu, Donald B. Brinkman, David A. Eberth and Dennis R. Braman.

Eotriceratops skull casting. Royal Tyrrel Museum, 2010.

I don’t think this picture does justice for it, so here’s what it may have looked like next to a standard Triceratops:

Eotriceratops size compared to Triceratops. Image by Conty, from Wikipedia.

There are some debates over the total lenght, but it’s quite larger than Triceratops. But then you can say “but PK, doesn’t ‘Eotriceratops’ mean “early Triceratops’? How can he be an adult Triceratops if he lived before Triceratops?”. Evidently the temporal range is estimative, and might not be entirely accurate; giving an error margin for this estimative, Eotriceratops would still be at the same time of Triceratops. If anything, Eotriceratops is the one that should have been theorized to be the aged Triceratops and be considered a synonym.

In his lecture Horner tries to argument there hasn’t been found any juvenile Torosaurus, but that’s false syllogism; I could, for example, argue that pterosaurs gave birth to live offspring since pterosaur eggs were never found. Except they were found, a few years ago, and they were soft-shelled eggs, for everyone’s surprise. What’s with this, you ask? Soft-shelled eggs are usually found in species that don’t take care of their offsprings, so this implicates that the scenario of mama pterosaur nurturing her babies in a nest, like birds do, is unlikely – but there might have been an exception here and there.

A female pterosaur preserved together with her egg. Lu Junchang, Institute of Geology, Beijing. Taken from CBC.

In other words, no juvenile Torosaurus was found because paleontologists have to rely on luck and patience, but some day they will be rewarded with such discovery. They found Tiktaalik, so why not?

The final hole in Horner’s theory is ceratopsian speciation. Amusingly enough, Horner himself kind of deliver that one: Early in his presentation, Horner show the growth series of the double-wattled cassowary, Casuarius casuarius, showing how different younger forms are compared to adult forms, and how the same thing could be applied to dinosaurs that could have been mistaken for separated species.

This is the dwarf cassowary, Casuarius benneti, and if the name is any clue, he’s a smaller cassowary. He’s native to Papua-New Guinea and nearby islands, but his range also overlaps with the population of double-wattled cassowaries, and his skull looks like this:

So comparing it with the double-wattled cassowary growth series, things get kind of interesting, because the dwarf cassowary’s skull looks a lot more like a younger form of the adult double-wattled cassowary. You could easily put the dwarf cassowary skull in the diagram and pretend you didn’t know these were different species.

Now think of a place with lots of similar species, such as the African savannah and its wounderful antelope species variety. Some might have similar characteristics one to another, but they are all unique in their own right, even if their skeletons are virtually identical.

Naturally if you were some kind of alien paleontologist in the future and you dug up antelope fossils, you could too think that the tiny dik-dik is just a baby gazelle, which in turn is the younger form of the sable since all you have to work with are their bones.

Maybe the reason Torosaurus looks a lot like Triceratops is because they are very closely related, and might have lived in the same areas, but this doesn’t mean they are one and the same.

In the end, Horner’s idea is just slightly interesting, but is inherently flawed. Some say what he’s doing is constructive trolling, making outrageous theories to incite other paleontologists to show their work. That would be acceptable (if a little annoying indeed), but my credibility on him was buried for good in the very first episode of Terra Nova, where he’s the paleontological consulter, and allows one character to point out that the brachiosaur “supplement their diets with small reptiles”. Damn.

Anyway, I hope you enjoyed this article, and as usual, any questions all you have to do is comment and I’ll answer it.